U.S. Pat. No. 4,597,138 discloses and shows a watch of this type wherein the male element is formed by a cylindrical pin fixed onto the horns of the case and the female element is formed by a concave cylindrical groove which forms the inner face of the insert. The insert is assembled on the cylindrical pin by means of a screw that is screwed into a threaded hole of the cylindrical pin and which forms the trunnion for the relative pivoting of the case in relation to the wristband. A return spring is inserted between the head of the screw and the outer surface of the insert so as to draw the insert towards its rest position. Thus, in order to pass to the pivoting position, a longitudinal force must be exerted outwards, against the return effort of the spring.
The rest position locking system provided in this Patent is not completely satisfactory since it is obtained by the return force of the spring. Consequently, when the spring is insufficiently stiff, this makes locking unreliable, which leads to a risk of inadvertent pivoting, particularly following an abrupt wrist movement by the user of the watch.
Moreover, the rest and pivoting positions are not precisely defined since the rest position towards the case is delimited solely by the insert abutting against the cylindrical pin or against the sheath that covers the same, and the pivoting position towards the exterior of the case is delimited solely by the total compression of the spring. Consequently, the user who manipulates this wristwatch in order to pivot the case feels some imprecision in the assembly of the parts. This imprecision may also worsen as the parts wear causing additional play in the assembly.
It is a particular object of the invention to overcome these drawbacks by proposing a simple and economical solution.